The present invention relates generally to switches used for coaxial radio frequency transmission lines and more particularly to an improved magnetic switch for use with such transmission lines.
The prior art related to switches for the control of radio frequency and high frequency transmission between signal input and signal output transmission lines have employed various mechanical devices including: spring actuated contacts, plungers, articulated joints and other movable elements to perform the switching action. These devices are subject to numerous deficiencies including: poor reliability, slow response time, lack of latching capability and relatively large insertion losses.
The prior art also includes U.S. Pat. No. 4,965,542 which incorporates a cavity in which one or more conductive contact members are movable from an open position, spaced away from pairs of line terminals, to a closed position, bridging one or more pairs of terminals. The contact members include magnetized strips or non-magnetic strips carrying magnets or magnetic members.
Despite the advances in the state of the art provided by the switches according to U.S. Pat. No. 4,965,542, there still remains a need for a coaxial switch which can accomplish the switching function without resorting to multiple solenoids. As an example, a single pole, triple throw, SP3T switch would typically require three solenoids, one for each position. This results in a switch which is relatively large in size, expensive, cumbersome, inefficient and unreliable.